Betty Friedan, perhaps the most important feminist in modern history, admits in "Life so Far" that the research that her book "The Feminine Mystique" was based on only included data from middle class housewives because middle class people were more important to her than lower class people culturally.
"The Feminine Mystique" is the most important book in feminist history because it ignited the second wave feminist movement, and the response to that book led to Betty creating the National Organization for Women which till the present day, is the feminist lobbying powerhouse unparalleled by any other feminist organization on the planet. So let's take a look at her words from page 131 of "Life so Far"
So you can clearly see her in that passage assuming that research based only on middle class women actually effected ALL women. So because her middle class, University classmates felt they were oppressed as women because they were housewives then that automatically meant that ALL women felt that they were oppressed as housewives! This is the farce that laid at the foundation of the feminist movement from the very beginning.